Diethers of polyoxyalkylene diols



Patented Aug. 29, 1950 UNITED I STATES T NT OFFICE I I 2,520,s12 I I e p ,DIETHERS or PoLYoxyAL rnanE nroLs Frederick HoffmanRoberts,"Charleston, W. Va.,

and Harvey RoweFife, Pittsburgh Pa -as signors, by mesne assignments, to. Union Car- V bide and Carbon Corporation, a, corporation oi? New York i No Drawing; Application January 8, 194?, 7

Serial No. 720,930 7 .5 Claims. (01. 250-515) a 1 I This invention relates ethers; that is, diethers of polyoxyalkylenediols or glycols. It is more particularly'concerned with compositions of relatively high average molecular weight which are complex mixtures of polyoxyalkylene diethers in which the polyoxyalkylene chains are composed predominantly of oxy, 1,2- propylene groups, OC2H3 JI-I3. By way of illustration, diethers in which the oxyalkylene chain is composed exclusively of oxy, 1,2-propylene groups may be represented by the formula Rooms-mm(hm-0119,40elm-0113011 ziolueisoi Z NaOH groups, and a: represents the number of oxy 1,2-.

propylene groups. Such diether compositions may be obtained, for instance, bythe etherification of a polyoxy 1,2-propylene diol composition, or their monoether compositions described in application Serial No. 538,098, filed May 30, 1944,

now'Patent No. 2,448,664;

" From such properties as average molecular -By way of illustration, a polyoxy 1,2-propylene diether composition made up of diethers having from 12 to 24 oxy 1,2-propy1ene groups to the polyoxyalkylene chain would have no less than eleven diether constituents difiering from one another in molecular weights, of which the proportion attributable to the polyoxy 1,2-propylene chain would range from 696 to 1276. Assuming each of these different diether constituents to be present in the mixture in the same mol proportion, the composition would have an average molecular weight such that the proportion attributable to the polyoxy 1,2-prODylene chain would be about 986. Tothese values for molecular weightsv and averagemolecular weights there 'is to be'.

added the molecular weight of. the terminal groups, 3 OR, having a minimum value of $6,

to polyoxyalkylene div desiredhowever; theproduct may be neutralized with ,carbon dioxide orphosphoric acid to the corresponding to dimethyl ether. The complexity of the mixtures seem to be due not only to difierences in'molecular' weights of the diether constituentabut also to the isomers arising out of the arrangement of the unsymmetrical 1,2-

propylene group within the molecules. The higher the average molecular weight ofthe diether composition the more complex may be the mixture. v

Using diethyl sulfate'as the etherifying agent, the reaction forproducing the ethyl diethers of the present invention from polyoxy 1,2-propylen'e diols 0r their'monoethyl ethers may be represented 'by the following equations:

.In general, in producing the diether compositions from the polyoxy 1,2-'propylene diols, with diethyl sulfatev as the etherifying agent, the reaction may -be-carried out using from two to four mols of the sulfate for each mol of the diol. Sodium hydroxide (solid); or other suitable alkali metal hydroxide, is also used in theproportion;

of. two m ols,of the hydroxide per mol of 'diethyl sulfate.; A -diluent or solvent for the reaction.

mixture, for instance dibutyl ether or toluene, may alsobe used, if desired. A mixture containing the diol, the solid caustic and a'diluent may be heated to aftemperature of about C. .or .C.,and to this heated mixture the diethyl sulfate, may ,be' added slowly, with stirring or agitation. The. reactionis exothermic, and the tern-Y perature is maintained at" about to Cjby cooling or by regulating the rate of addition of the'diethyl'sulfate or both. In the absence of a solvent or diluent, the reaction mixture may tend.

to become gelatinous-if'the amount of'caustic is relatively'large and theaverage molecular weight ofthe diolis low.

When all of the-diethyl sulfate has been added, the temperature of the reaction mixture is held between 90 and-.100 C. over a period of three to five hours, with continued'stirring to complete the reaction; If the temperature is permitted to increase during this period, some diethyl etherv may beevolved. The product is then washed severaltimes with water at a temperature of about 80 C.;until a pH range'of-about 7 to 8 results. If

samepH value. Following. the washing, the diether composition will, usually be found in the top layer. It .is stripped "of water, diluent, and

inorganic impurities having a catalytic action favoring the rupture of the-oxyalkylene chain are much less soluble in the diether compositions than.

in the diols or their monoethers, thus affording a higher stability of the diethers, particularly at elevated temperatures. 7

The polyoxy 1,2-propylene diethers exhibit also a higher degree of water-immiscility than do the diols or the monoethers from which diethers may be prepared. They are less water-miscible also than polyoxyalkylene. diols and mono anddiethers thereof containing a substantial proportion of oxyethylene groups in the oxyalkylene chain;

In general, the higher the average molecular weight of the diether compositions, the less the influence of the size of different aliphatic ether groups on the propertie For instance, in a methyl, methyl diether composition, the weight attributable to the dimethyl ether grouping, CHaOCI-Ia, would amount to about ten per cent of an average molecular weight of 500, whereas for an octyl, octyl diether, the dioctyl ether grouping, CaH17OC8l-I1'z,would constitute about half.

The compositions with which this invention is more particularly concerned are those in which the portion of the average molecular weight attributable to the oxyalkylene groups is about 800 or more, with an average molecular weight of at least 846 for the polyoxy 1,2-propylene methyl, methyl diether composition and 1042 for the octyl, octyl diether composition, byway of illus tration, and with correspondingly higher aver- .age molecular weights for the higher aliphatic Example 1 r A polyoxy1,2-'propylene methyl, ethyl diether composition having an average molecular weight of about 910, determined ebullioscopically, was made by the action of diethyl sulfate on a poly oxy 1,2-propylene methyl monoether monohydroxy composition having an average molecular weight of about 907, by acetyl value, and a viscosity of 43.6 centistokes (202 S. U. S.) at 100 F.

The diether composition was found to have a viscosity of 29.7 centistokes (139 S. U. S.) at 100 F., and 6.72 centistokes (48.1 S. U. S.) at 210 F., a specific viscosity in benzene solution of 0.1195 at 18 C., a density of 0.9202 at 210 F., and a refractive index of 1.4430 at 20 C.

Example 2 Polyoxy 1,2-propylene ethyl, ethyl diether compositions having average molecular weights of 857 and 1660, determined ebullioscopically, and viscosities of 42.2 centistokes (195 S. U. S.) and 191 centistokes (882 S. U. S.) at 100 F., were made by the action of diethyl sulfate on polyoxy 1,2-propylene dihydroxy compositions having average molecular weights of 1229 and 3259 by acetylation, and viscosities of 88.7 centistokes (410 S. U. S.) and 265 centistokes (1224 S. U. S.) respectively, at 100 F.

6 1.. The ethyl, ethyl diethercompositions were, found to-have the following properties: I

Viscosity, Centistokes Renae; I M01. f tive Denslty Weight g o o Bemene Ind ex 210 F.

20 F. F. 210 F. at 0 Q at 20 O.

The ratios of viscosity at 20 F. to that at 210 F. were calculated to be 55.4 and 109, corresponding to viscosity indices (ASTM) of andl40, respectively.

Example 3 Polyoxy 1,2-propylene butyl, ether diether compositions having average molecular weights of about 935, 950, 1105 and 1470, determined ebullio scopically, and viscosities of 32.8. centistokes (153 S. U. S.) 36.96 centistokes (172 S. U. S.), 69.0 centistokes (319 S. U. S.) and 140 centistokes (647s. U. S.) at 100 F., were made by the action of diethyl sulfate on polyoxy 1,2-propy1ene monohydroxy monobutyl ether compositions having average molecular weights of 940, 936, 119 3, 1540, by acetyl value, and viscosities of 47.5, 51.4,,

87.5, and 176 centistokes, respectively, at a temperature of 100 F.

The ratio of the viscosity at 20 F. to thatiat 210 F. was calculated to be 41.8, 45.6, 65 and 79, respectively. l

Example 4 A polyoxy 1,2-propylene butyl, normal propyl diether composition having a viscosity of about 26.3 centistokes (125 S. U. S.) at 100 F. was made by the action of normal propyl bromide vand sodium hydroxide on a po-lyoxy 1,2-propylene monohydroxy butyl monoether composition. hav'f ing an average molecular weight of about 838, by acetylation, and a viscosity at 100 F. of about 37.6 centistokes (175 S. U. S.).

The butyl, propyl diether composition was found to have viscosities of 26.1 centistokes (125 S. U. S.) at 100 F. and 6.14 centistokes (46.3 S. U. S.) at 210 F., a specific viscosity in benzene solution at 18 C. of 0.1131, a density of 0.9077 at 210 F. and a refractive index of 20 C. of 1.4438.

Example 5 Polyoxy 1,2-propylene butyl, butyl diether compositions having viscosities of 39.05 centistokes (181 S. U. S.) at 100 F. and 69.4 centistokes (321 S. U. S.) at 100 F., respectively, were made by the action of normal butyl chloride and sodium hydroxide on polyoxy 1,2-pr0pylene butyl monoether monohydroxy compositions having average molecular weights of about 936 and 1193, by acetylation, and viscosities of 51.4 centistokes (238 S. U. S.) and 87.5 centistokes (404 S. U. S.) at 100 F. and 10.15 centistokes (59.7 S. U. S.) and attests 13*.1 centis tokes (tar-s. us), respectively, at 210 F.

butyl 'diether compositions were The butyl,

found to have the following properties-z Viscosity, (lent istokes Rehm? V a. M01-. it m v Dens Weight o o Begum lnd ex at210" F.

M 20 r. 100 F. 210 F. c CI at20 0.

The ratio of the visoosity at'20 F. to that at 210 F. was calculated to be 51.4 and 76.4, respectively, for each of the diether compositions.

Example 6 A po'lyoxy l,2spropylene butyl, normal o'ctyl diethe'r composition having an average molecular weight of about 950, determined ebullioscopically, and a viscosity of about 40.79 centistokes (189 S. U. S.) at 100? R, was made by the action of normal octyl chloride and sodium hydroxide on a polyoxy 1,2-propylene' monobutyl ether monoh'ydrox'ycomposition having an average molecularweight of about 936 at100 F. and viscosities of 51.4 cent'istokes (238 -S U. S.) at 100 F. and 10.15 cent'istokes (59.7 S. U. S.) at 210" The resulting butyl, normal octyl diether composition was found to have viscosities of 426, 40.79

1 and 8.98 centistokes at temperatures of 20" 100 and 210": F., a specific viscosity in benzene at 18 c. of 0.1452, and a refractive index at 20C. of

1 The who of Its Vlscoslty at 20 F m that alkyl ether groups have a total of eight carbon at 210 F. was calculated to be 47.5.

: 7 Example 7 A 'polyoxy '1, 2-propylene butyl, normal dodecyl diether composition having a viscosity of about 43.95 centistokes (204 S. U. S.) at 100 F. was

and sodium hydroxide on a polyoxy l,2-'propylene mohobutyl ether monohydroxy composition havand 9.47 centistokesat temperatures f100 F. and 210 F., respe'c tively; a specific viscosity in benzene at 18C. of 0.1555, a refractive index at 20 C. or 1.4473, and a density at 210 of 0.8057. The composition was solid at a temperatureof 20 F.

The term viscosity index as used herein corresponds to the conventional viscosity index cal culatio'n's for etroleum products and lubricants in accordance with the definitions accepted by the 1 American Society for Testin Materials (see industrial and Engineering Chemistry (1935), vol- '1. A normally liquid mixture of alkyl diethe'r's of polyoky 1,2 -propylehe diols having an averagemolecular weight such that the portion thereof attributable to ox l,2-propylene groups is' at least 800. i l H 2. A normally liquid mixture of alkyl diethers 1 of polyoxy l,2 -propylene diols in which the alkyl ether groups have from one to eight carbon atoms and having an average molecular Weight such that the portion thereof attributable to oxyatoms, said mixture having an average molecular weight such that the portion thereof attributable to oxy l,2-'propyle ne groups is at least 800.

5. A normally liquid mixture of polyo'xy' 1,2- propylene butyl, butyl diethers, said mixture hgtving an average molecular weight of at least 9 0.

FREDERICK HOFFMAN ROBERTS. I

ROWE FIFE.

REFERENCES CITED The tollowi-ng references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,614,888 Davidson Jan. 18, 1927 2,425,755 Roberts Aug. .19, 1947, 2,425,845 Toussaint Aug. 19, 1947 

1. A NORMALLY LIQUID MIXTURE OF ALKYL DIETHERS OF POLYOXY 1,2-PROPYLENE DIOLS HAVING AN AVERAGE MOLECULAR WEIGHT SUCH THAT THE PORTION THEREOF ATTRIBUTABLE TO OXY 1,2-PROPYLENE GROUPS IS AT LEAST
 800. 